Centrifuges provide a very common method for separating mixtures in a laboratory setting. Sample mixtures in need of separation are placed in a plurality of individual containers called “centrifuge labware.” The samples are then rotated at high speed within the centrifuge until the various components of the mixture are separated by centrifugal force. The most commonly used centrifuges are designed to handle labware of relatively small volume. The labware is typically test tube shaped and the labware is disposed within the centrifuge at a fixed angle with respect to the vertical.
For separating samples of larger volume, swinging bucket centrifuges are employed. Such swinging bucket centrifuges are designed to handle labware having a volume capacity of up to a liter or more. In a swinging bucket centrifuge, the labware is initially retained within hinged buckets, such that the labware is initially retained in a vertical orientation. During operating of the centrifuge, centrifugal forces acting on the bucket cause the buckets to rotate about the hinges outwardly whereby the labware becomes disposed at an angle with respect to the vertical.
Large volume labware is commonly used to grow and eventually harvest genetically engineered bacteria and other simple cellular materials. The bacteria and/or other cellular materials are grown within a nurturing liquid (“broth”) disposed within large “fermentors” having a typical capacity of 1-1000 liters. At the end of the growing cycle, a portion of the nurturing liquid is placed into the labware and the labware is then loaded into a swinging bucket centrifuge. In the centrifuge, the labware is rotated at high speed until the biological material is concentrated at the bottom of the labware in a mass commonly termed a “pellet.” After separation in the centrifuge, the remaining liquid material (“supernatant”) is decanted off and the pellet is “harvested,” typically by scraping the pellet off of the bottom of the labware using a spatula or similar tool.
Prior art large volume labware useable in such biotechnical, bioindustrial and biopharmaceutical applications typically are containers having flat bottoms, narrow openings and a screw top lid. There are several problems inherent in such labware. The flat bottoms mean that the junction of the bottom wall with the vertical side walls defines a circumferential edge where it may be difficult to remove the pellet. Moreover, in prior art labware having a non-round cross-section, the junction of the bottom wall with the vertical side walls will also define a plurality of corners from which it can be very difficult to remove pellet material.
In addition, the relatively narrow opening at the top of such prior art labware makes it difficult to remove pellets from the bottom of the labware.
Still further, the screw top lid of such prior art labware does not seal well in the centrifuge. This is because when the centrifuge is operating, the container portion of the labware tends to elongate under the high centrifugal forces. Such elongating of the container portion tends to narrow the top opening and loosens the seal with the screw cap.
Yet another problem with such prior art labware is the relative impossibility of constructing and using a practical liner which will protect the labware and facilitate the cleaning of the labware.
Yet still another problem with such prior art labware is the relative difficulty of decanting off liquid material through the top opening without spilling or dribbling some of the liquid material. Because the liquid material can contain potentially toxic material, this can pose a health risk to laboratory personnel.
Accordingly, there is a need for centrifuge labware which avoids some or all of the aforementioned problems in the prior art.